THURSDAY, Feb. 13, 2014 (HealthDay News) -- Waking up and not feeling rested isn't just annoying. Researchers say that "non-restorative sleep" is the biggest risk factor for the development of widespread pain in older adults.

Widespread pain that affects different parts of the body -- the main characteristic of fibromyalgia -- affects 15 percent of women and 10 percent of men over age 50, according to previous studies.

To identify the triggers of such widespread pain, British researchers compiled demographic data as well as information on the pain and physical and mental health of more than 4,300 adults older than 50. About 2,700 had some pain at the study's start, but none had widespread pain.

The results, published Feb. 13 in Arthritis & Rheumatology, show that restless sleep as well as anxiety, memory problems and poor health play a role in the development of this type of pain.

Three years after the study began, 19 percent of the participants had new widespread pain, the researchers found.

This new pain in various parts of the body was worse for those who had some pain at the beginning of the study. Of those with some prior pain, 25 percent had new widespread pain. Meanwhile, 8 percent of those with no pain at the start of the study had widespread pain three years later.

"While osteoarthritis is linked to new onset of widespread pain, our findings also found that poor sleep, [memory], and physical and psychological health may increase pain risk," concluded the study's leader, Dr. John McBeth, from the arthritis research center at Keele University in Staffordshire, England.

"Combined interventions that treat both site-specific and widespread pain are needed for older adults," McBeth added in a journal news release.

Increasing age, however, was linked to a lower chance of developing widespread pain. Muscle, bone and nerve pain is more common among older people. Up to 80 percent of people 65 and older experience some form of pain on a daily basis, according to the news release.

While the study finds an association between poor sleep and widespread pain, it does not establish a direct cause-and-effect relationship.